This invention relates to a temporary and disposable ventricular cardiac pacemaker, and more particularly to a pacemaker which transmits pulses at a selected rate to barbless hook electrodes that are inserted and held in a patient's heart.
In cardiopulmonary bypass surgery, the heart is generally stopped during surgery, and an oxygenator is used to supply blood to the patient during the surgical operation. Upon completion of surgery, it is frequently necessary to restart the heart by stimulating the heart muscle with an electrical pulse. To do this, surgeons use a temporary pacemaker device.
Further, during circumstances when the heart stops or is too slow to function properly prior to cardiopulmonary bypass, there is need for a temporary device which can be applied quickly and removed easily once cardiopulmonary bypass has been initiated.
The temporary pacemaker devices in use today have two separate wires, each approximately two feet long with each wire having a sterile needle attached at an end thereof. With these devices, the wires are surgically stitched to the heart tissue to provide an electrical connection. After connecting the wires to the heart, the needles are then pushed through the chest wall, at a position spaced from the incision used for heart surgery, and the wires are led outside the chest wall. The needles are formed so that each may be snapped in two leaving a stub still connected to the corresponding wire. The stub is then inserted in a female electrical connector connected to an electrical cable which in turn is connected to an external, battery-operated, pulse generator which is used to provide electrical pulses to the heart.
With these conventional temporary pacemakers wires are connected to the pulse generator and are subject to being knocked loose and must be repositioned or replaced. Upon completion of surgery, the pacemaker wires must either be removed or passed through the skin of the chest wall.
There is a recognized need for a temporary pacemaker assembly which can be used briefly during surgery until the heart starts beating on its own, to provide an effective means for attaching electrodes to the heart while avoiding the use of stitched connections and long leads that can be knocked loose. There is also a need for a pacemaker where any leads or electrodes used with a particular patient can be disposed of after use at the conclusion of surgery. Further, there is a need for a temporary pacemaker where the connector between the pacemaker pulse transmitting portion and the pacemaker lead can readily be cleaned of blood or other contaminants before the pulse transmitting portion of the assembly is reused.
Pacemaker devices are well known and the electrode assemblies for attaching pacemaker electrodes to a patient's heart are also known in the art. U.S. Pat. No. 4,607,644 to Pohndorf and U.S. Pat. No. 4,177,818 to De Pedro both illustrate barbless hook electrodes which can be inserted into a heart, the electrodes receiving electrical pulses to stimulate a patient's heart. In both of these patented devices, the electrodes are intended to be used with pacemakers implanted under a patient's skin and thus are designed for long-term implantation. The electrodes are not easily used in a surgical environment for temporary use.